从NLRP3炎症小体途径探讨竹节参总皂苷改善自然衰老大鼠认知功能衰退的作用机制

探讨竹节参总皂苷(saponins from Panax japonicus,SPJ)对自然衰老大鼠认知功能衰退的改善作用及机制。18月龄SD雄性大鼠随机分为3组,即自然衰老组、竹节参总皂苷10 mg·kg~(-1)和30 mg·kg~(-1)剂量组,每组10只。竹节参总皂苷给药组大鼠从18月龄开始分别灌胃给予10,30 mg·kg~(-1)竹节参总皂苷,自然衰老组大鼠灌胃等量的生理盐水。灌胃持续6个月,每周连续灌胃6 d,停药1 d,另取10只6月龄的大鼠作为青年对照组。采用旷场、新物体认知和Morris水迷宫方法检测各组大鼠认知功能的改变,场电位记录法检测各组大鼠海马CA1区突触传递长时程增强(LTP)的变化。Western blot法检测各组大鼠NLRP3炎症小体相关蛋白NLRP3,ASC,caspase-1的表达变化以及突触可塑性相关蛋白Glu A1,Glu A2和学习记忆相关蛋白CAMKⅡ,CREB及其磷酸化表达的变化。竹节参总皂苷可改善衰老大鼠的认知功能衰退,减轻衰老大鼠海马CA1区LTP的受损程度,减少衰老大鼠NLRP3炎症小体相关蛋白NLRP3,ASC,caspase-1的表达水平。同时,竹节参总皂苷可增强突触可塑性相关蛋白AMPA受体亚型Glu A1和Glu A2的膜表达,增强衰老大鼠学习记忆相关蛋白CAMKⅡ,CREB的磷酸化表达水平。竹节参总皂苷可改善衰老大鼠认知功能衰退,其机制可能与其调节NLRP3炎症小体,进而调节AMPA受体膜表达,增强学习记忆相关蛋白CAMKⅡ和CREB的磷酸化表达有关。     

离子型谷氨酸受体参与学习和记忆分子机制的研究进展

学习和记忆是脑的高级功能，是一个相当复杂的生理过程，目前认为学习记忆机制是突触传递效能的长时程增强（Longterm potentiation，LTP），被认为是学习与记忆的一个细胞模型。LTP的形成与突触前递质的释放、突触后相关受体通道以及各种蛋白激酶、逆行信使、即早基因等密切相关。     

刺五加皂苷对癫痫大鼠水迷宫成绩和海马PS幅度的影响

目的观察刺五加皂苷对青霉素诱导的癫痫大鼠学习记忆的影响。方法青霉素诱导大鼠癫痫模型后,腹腔注射刺五加皂苷,通过水迷宫实验和在体细胞外记录海马CA3区群峰电位长时程增强(LTP)的变化,观测刺五加皂苷对癫痫大鼠学习记忆的影响。结果①癫痫发作延长大鼠水迷宫游泳时间;②癫痫发作降低大鼠海马CA3区PS幅度;③刺五加皂苷能缩短癫痫大鼠水迷宫游泳时间;④刺五加皂苷能升高癫痫大鼠海马CA3区PS幅度。结论刺五加皂苷可能对青霉素致痫大鼠学习记忆的损伤有显著改善作用。     

刺五加对睡眠剥夺大鼠学习记忆及海马LTP的影响

目的研究刺五加对睡眠剥夺大鼠学习记忆能力及海马长时程增强的影响。方法采用小平台法建立快速眼动睡眠(REMS)剥夺大鼠模型,利用行为学及神经电生理学方法,观察刺五加对其学习记忆能力及海马突触长时程增强(LTP)的影响,探讨刺五加对睡眠剥夺造成的学习记忆损害的保护作用及作用机制。结果与大平台对照组比较,睡眠剥夺组错误次数增多、认知率降低,且差异显著(P<0.01),但寻找时间缩短(P<0.05);在刺五加干预下,错误次数明显减少、认知率升高(P<0.01),寻找时间缩短(P<0.01)。睡眠剥夺组大鼠LTP明显受到抑制,高频刺激(HFS)引起的群峰电位幅值及兴奋性突触后电位斜率的增大明显低于大平台对照组(P<0.01),各剂量给药组对睡眠剥夺引起的LTP抑制现象均有明显恢复作用(P<0.01)。结论睡眠剥夺能引起动物学习记忆能力的降低,刺五加可对抗此作用,其机制可能与改善神经突触可塑性有关。     

调心方对麻醉大鼠海马长时程增强的作用

目的 :观察调心方对麻醉大鼠海马诱发长时程增强 (LTP)的易化和增强作用。方法 :采用麻醉大鼠海马诱发LTP实验技术 ,以 60Hz 2 0串、60Hz 3 0串和θ波串为串刺激分别诱发LTP ,串刺激前 3 0min单次口服给予调心方。结果 :单次口服给予调心方 (5 5 88g/kg)对大鼠海马穿通路正常的突触活动和LTP的维持均没有产生影响 ,但其可以提高大鼠海马穿通路LTP的诱发成功率。结论 :调心方具有一定易化LTP生成的作用 ,这可能是其改善学习记忆功能的机制之一。     

电针对吗啡戒断大鼠学习记忆及海马CA3区长时程增强损害的恢复作用

目的 :观察电针对吗啡戒断大鼠学习记忆能力及海马外侧穿通纤维CA3区直接传导通路长时程增强 (LTP)损害的恢复作用 ,并探讨其机制。方法 :慢性腹腔注射吗啡建立SD大鼠吗啡依赖模型。在“足三里”和“三阴交”两穴位处给予吗啡依赖和戒断大鼠多次和单次电针治疗 ,并测试学习记忆能力 ,记录CA3区群体峰电位 ,及观察高频刺激引起的LTP效应。结果 :吗啡戒断大鼠学习记忆能力和LTP效应均受损 ,单次电针治疗对其有一定恢复作用 ,多次电针治疗能完全恢复被损害的学习记忆能力和LTP ,电针效应能被阿片受体抑制剂纳络酮所阻断。结论 :电针穴位通过内源性阿片系统调制吗啡戒断大鼠的突触可塑性。     

补肾益气方药对老年大鼠空间学习记忆能力及相关蛋白表达的影响

目的观察补肾方药(左归丸)、益气方药(益气聪明汤)及两方合用(合剂)对老年大鼠血清皮质酮水平、海马长时程增强(LTP)、空间学习记忆能力及突触蛋白I(Synapsin-I)表达变化的影响。方法以自然衰老(24月龄)SD雄性大鼠为动物模型,随机分为老年对照组、老年左归组、老年益气组、老年合剂组和老年皮质酮(GC)拮抗组,另设青年对照组(同品系5月龄SD雄性大鼠)。采用ELISA法检测大鼠血清皮质酮含量,Morris水迷宫法观察各组大鼠空间学习记忆能力,电生理方法记录各组大鼠在体LTP变化,Western blotting法检测各组大鼠海马组织Synapsin-I表达变化,同时观察左归丸、益气聪明汤及合剂对上述指标异常变化的改善作用。结果与青年对照组相比,老年对照组大鼠的血清皮质酮含量明显升高(P0.05),空间学习记忆能力显著下降,海马CA1区LTP明显受到抑制(P0.05),Synapsin-I表达明显降低(P0.05);左归丸、益气聪明汤及合剂均能不同程度改善上述指标的异常变化,但合剂对Synapsin-I表达量变化的影响无统计学意义。结论补肾方药左归丸、益气方药益气聪明汤可增加老年大鼠突触可塑性(LTP)和Synapsin-I蛋白表达,进而改善老年大鼠空间学习记忆能力,可能与拮抗高皮质酮对老年大鼠海马神经细胞结构与功能的损伤有关。     

调心方对大鼠海马脑片长时程增强效应的影响

目的：观察调心方对大鼠海马脑片长时程增强（LTP）效应的影响。方法：采用细胞外微电极技术，记录大鼠海马脑片CA1区细胞外群峰电位（PS），然后施以100hz,100串的强直刺激，诱发LTP产生。结果：在正常情况下，大鼠海马脑片LTP的诱发成功率约为60％，施以高频串刺激后PS幅度显著增高，PS潜伏期明显缩短，用调心方（7.45mg/ml）预先孵育海马脑片对正常PS的形状，幅度均无明显影响，提示其并不影响海马脑片的基础突触传递，但施以高频刺激后脑片LTP的诱发率呈现升高趋势，同时其PS增幅与正常对照组比较也显著提高，结论：调心方可提高大鼠海马脑片LTP的诱发率及增幅，这可能是其改善海马学习记忆功能的作用机制之一。     

蛇床子素对麻醉大鼠中枢长时程增强现象的影响

目的:探讨蛇床子素对大鼠海马齿状回突触传递活动的影响。方法:采用高频电刺激诱导LTP的电生理学方法,在体记录并观察不同剂量蛇床子素对麻醉大鼠海马齿状回长时程增强现象的影响。结果:侧脑室注射蛇床子素5μl后,各实验组在给予HFS后均有LTP现象出现,各剂量组的PS幅值在180min内维持较高水平,至HFS后180min时,30ng,15ng,5ng各剂量组PS幅值变化率分别为248%±18%,238%±11%,212%±14%,与对照组相(173%±8%)相比显著增大(P<0.01)。结果表明,侧脑室注射蛇床子素30ng,15ng,5ng对HFS诱导大鼠海马齿状回LTP有增强作用。结论:蛇床子素对大鼠海马齿状回突触传递活动有明显促进和增强作用,对提高大脑学习、记忆能力有益。     

刺五加皂苷对衰老大鼠学习记忆功能和海马CA1区长时程增强的影响

目的:观察刺五加皂苷对D-半乳糖所致衰老大鼠学习记忆功能和海马CA1区LTP的影响,探讨其可能的机制。方法:将27只大鼠随机分为对照组、D-半乳糖组和ASS组。D-半乳糖注射建立衰老大鼠模型,ASS组腹腔注射ASS干预。水迷宫检测大鼠的学习记忆能力。电生理实验比较强直刺激前后海马CA1区PS幅度变化。结果:在水迷宫实验中,ASS能明显改善衰老大鼠的学习记忆功能。电生理实验中,模型组强直刺激后平均PS增幅明显低于对照组,ASS组中衰老大鼠的PS增幅提高。结论:ASS能提高衰老大鼠的学习记忆能力,并改善D-半乳糖对大鼠海马CA1区LTP的抑制。     

穴位埋线对血管性痴呆大鼠学习记忆和长时程增强的影响

目的:探讨穴位埋线对血管性痴呆(VD)大鼠学习记忆的影响及可能的机制。方法:改良Pulsinelli’s四血管阻断法建立血管性痴呆大鼠模型;在造模后给予穴位埋线治疗;采用Morris水迷宫检测学习记忆能力;在体记录海马齿状回长时程增强(LTP),观察并比较各组于高频刺激(HFS)后的变化。结果:经穴位埋线后,与模型组比较,VD大鼠水迷宫成绩显著提高(P<0.05,P<0.01);海马齿状回LTP在HFS后群体峰电位(PS)幅值、PS斜率显著增加(P<0.05,P<0.01)。结论:穴位埋线可改善血管性痴呆大鼠的学习记忆能力,可能与易化VD大鼠海马齿状回的LTP有关。     

Promotive effect of ginsenoside Rd on proliferation of neural stem cells in vivo and in vitro

Ethnopharmacological relevance

Ginseng, the root of Panax ginseng C. A. MEYER (Araliaceae), is reputedly known for its nootropic and anti-aging functions and has been widely used to treat various diseases and enhance health for thousands of years in Asia. Recent studies revealed that ginsenoside, responsible for the pharmacological effects of ginseng, can prevent memory loss and improve spatial learning in mice, but underlying mechanisms are still largely unknown. Active neurogenesis in adult hippocampus is closely related to animals' learning and memory ability. The present study aimed to investigate the possible effects of ginsenoside Rd, one of the most effective ingredients in ginseng, on neurogenesis in vivo and in vitro.

Materials and methods

Adult rats and cultured neural stem cells were treated with ginsenoside Rd at different doses, and the changes in the proliferation and differentiation of neural stem cells were examined by immunohistochemistry and immunocytochemistry.

Results

Ginsenoside Rd significantly increased the numbers of BrdU⁺ and DCX⁺ cells in the hippocampal dentate gyrus but did not affect the ratio of NeuN/BrdU double-labeled cells to the total number of BrdU⁺ cells. For cultured neural stem cells, ginsenoside Rd promoted the size and number of neurospheres, increased the number of BrdU⁺ and Ki67⁺ cells but did not affect the differentiation of neural stem cells into neurons, astrocytes and oligodendrocytes.

Conclusions

These results indicate that ginsenoside Rd can enhance the proliferation but not affect the differentiation of neural stem cells in vivo and in vitro.     

电针对半乳糖所致大鼠空间学习记忆障碍及海马齿状回LTP诱导的干预作用

本文研究了D 半乳糖对大鼠空间学习记忆行为及对在体诱导海马齿状回LTP的影响 ,并观察了电针的干预作用。正常组每日皮下注射生理盐水 1mL ,模型组和电针组每日皮下注射D 半乳糖 ( 80 0mg/kg)共 6周 ,电针组从第 1 8天开始电针。空间学习记忆行为以Morris水迷宫潜伏期作为判定标准 ;应用记录单脉冲刺激穿通纤维在海马齿状回诱发的群体电位 ,测量高频刺激(HFS)前后单脉冲刺激诱发的电位幅值变化 ,将HFS前的记录作为对照值 ,进行组间比较。结果显示 :①模型组水迷宫潜伏期成绩明显低于正常组 ,电针组潜伏期成绩与模型组比显著提高 (P <0 .0 5) ;②HFS前记录显示 :三组间PS潜伏期和PS平均幅值无显著性差异 ,HFS后 ,1 0只正常组大鼠有 8只产生了LTP。其电位平均幅值增加为基线值的 1 3 5± 3 .9% ;1 0只模型组大鼠有 2只产生了LTP ,其平均值为基线值的 1 2 1 .4± 1 .4% ;电针组 9只大鼠有 5只产生了LTP ,其平均幅值为基线值的 1 3 1 .8± 5.3 %。提示 :D 半乳糖可损害大鼠的空间学习记忆能力、降低大鼠在体海马齿状回LTP的诱导率 ,降低LTP振幅 ;电针可提高模型动物的空间学习记忆能力 ,阻抑半乳糖对LTP诱导的损害作用     

Oleuropein Improves Long Term Potentiation at Perforant Path-dentate Gyrus Synapses in vivo

Objective To investigate the effect of oleuropein(OE) on long term potentiation(LTP) at hippocampal perforant path-dentate gyrus synapses in vivo. Methods An outer guide cannula, a monopolar recording electrode, and a bipolar stimulating electrode were implanted in the skull and extracellular recording technique was used to record the population spike in the dentate gyrus of anesthetized rats. Results Oleuropein significantly increased the basal synaptic transmission and the amplitude of population spike was increased from(117.6 ± 2.3)% to(134.9 ± 3.7)% after administration with OE.OE also accelerated LTP induction and maintenance, the population spike amplitude after high frequency stimulation was increased from(167.2 ± 12.8)% to(225.5 ± 15.5)% and the maintenance phase of LTP was from(182.1 ± 15.1)% to(210.5 ± 9.0)% respectively after administration with OE. Conclusion Present study showed that OE significantly improved different stages of LTP, which could be the molecular mechanism of its efficacy on attenuating AD-like pathology and delaying cognitive decline. OE can be a promising drug for AD and dementia.     

人参皂苷Re在大鼠体内的代谢研究

目的:研究人参皂苷Re在大鼠体内的代谢情况并了解其代谢产物.方法:将6只SD大鼠按100mg·kg~(-1)灌胃给予人参皂苷Re,收集给药后12,24,36,48,60,72h粪便,预处理后采用HPLC-ESI-Ms/Ms方法,以人参皂苷Re的微生物转化产物为对照品,检测大鼠体内的代谢产物.结果:在大鼠体内共检测到6个代谢产物,并利用对照品鉴定了它们的结构分别为:20(S)-人参皂苷Rg2,20(S)-人参皂苷Rh_1,20(R)-人参皂苷Rh_1,人参皂苷F_1,3-羰基人参皂苷Rh,和原人参三醇.结论:人参皂苷Re在大鼠体内的代谢产物较多,且与微生物转化产物具有很强的相似性.     

Antibiotics attenuate anti-scratching behavioral effect of ginsenoside Re in mice

Ethnopharmacological relevance

The root of Panax ginseng CA Meyer (ginseng) has been used for diabetes, cancer, stress and allergic diseases in the traditional Chinese medicine.

Aim of the study

To understand the role of intestinal microflora in the pharmacological effect of ginsenoside Re, which is a main constituent of ginseng, we investigated its anti-scratching behavioral effect in the mice treated with or without antibiotics.

Materials and methods

Ginsenoside Re was orally administered to the mice treated with antibiotics (cefadroxil, oxytetracycline and erythromycin mixture (COE), streptomycin or/and tetracycline) and then investigated the relationship between ginsenoside Re-metabolizing β-glucosidase and α-rhamnosidase activities of intestinal microflora and its antiscratching behavioral effect. The anti-scratching behavioral effects of ginsenosides were investigated in the increments of 1 h and 6 h after their oral administrations. The scratching behavioral frequency was measured for 1 h after treatment with histamine.

Results

Ginsenoside Re inhibited histamine-induced scratching behavior in mice. The anti-scratching behavioral effect of ginsenoside Re was more potent 6 h after its oral administration than 1 h after. However, its inhibitory effect was significantly attenuated in mice treated with COE, but it nearly was not affected in mice treated with streptomycin and/or tetracycline. Treatment with COE also significantly lowered fecal ginsenoside Re-metabolizing β-glucosidase and α-rhamnosidase activities in mice, as well as fecal metabolic activity of ginsenoside Re to ginsenoside Rh1. The anti-scratching behavioral effect of ginsenoside Rh1, a metabolite of ginsenoside Re by intestinal microflora, was superior to that of ginsenoside Re. Ginsenoside Rh1 potently inhibited the expression of IL-4 and TNF-α, as well as the activation of NF-κB and c-jun activation in histamine-stimulated scratching behavioral mice.

Conclusion

Ginsenoside Re may be metabolized to ginsenoside Rh1 by intestinal microflora, which enhances its anti-scratching behavioral effect by inhibiting NF-κB and c-jun activations.     

Chronic toxicity of ginsenoside Re on Sprague-Dawley rats

Ethnopharmacological relevance

Ginseng has been widely used for hundreds of years in both China and other countries. It is well accepted that the pharmacological effects of ginseng are attributed to ginsenosides. Ginsenoside Re is one of the active ingredients in ginseng. The present study was carried out to characterize the toxicity of ginsenoside Re after repeated oral administration in Sprague-Dawley rats.

Materials and methods

Rats (60 males, 60 females) were administrated ginsenoside Re orally in 0, 38, 113, or 375 mg/kg/day doses for 26 weeks (n=15/group each sex). Clinical signs, mortality, body weights, feed consumption, urinalysis, hematology, serum biochemistry, gross findings, organ weights and histopathology were examined at the end of the test period, as well as after the 4-week recovery period.

Results

Ginsenoside Re did not induce death, adverse effects or dose-dependent changes in feed consumption, or body weight gain. Some statistically significant differences were observed in hematological and biochemical parameters, as well as in body weights of rats treated with ginsenoside Re. However, there was no abnormality of any organs noted in both gross and histopathological examinations.

Conclusions

Ginsenoside Re is well tolerated up to a 375 mg/kg/day oral dosage level and non-toxic in both male and female rats.     

复智胶囊对血管性痴呆模型大鼠海马神经元突触传递长时程增强的影响

目的:观察复智胶囊对血管性痴呆大鼠海马神经元突触传递长时程增强(long-term potentiation,LTP)的影响。方法:SPF级雄性SD大鼠采用双侧颈总动脉永久结扎法(2-VO)制备血管性痴呆大鼠模型。选取造模成功的大鼠,随机分为模型组、多奈哌齐(0.52×10-3g·kg-1·d-1,ig)组、复智胶囊高、低剂量(6.30,3.15 g·kg-1·d-1,ig)组。并设假手术对照组。连续ig 4周后,采用Morris水迷宫检测实验大鼠的学习记忆能力,同时采用LTP诱导法检测大鼠海马齿状回高频刺激诱发的群峰电位(population spike,PS)幅值变化,采用免疫组化检测海马N-甲基-D-天门冬氨酸(NMDA)免疫阳性细胞的表达。结果:与假手术组相比,造模术后的大鼠学习记忆能力均有下降,逃避潜伏期和游泳路程明显延长,撤除平台后跨越原平台次数明显减少,高频电刺激后海马神经元齿状回PS增幅明显下降,海马NMDA免疫阳性细胞数明显减少,差异均有统计学意义(P<0.05);而与模型组相比,复智胶囊高、低剂量组和多奈哌齐组大鼠学习记忆能力均有改善,逃避潜伏期和游泳路程均有缩短,跨越原平台次数明显增多,海马神经元齿状回PS增幅明显升高,海马NMDA免疫阳性细胞数明显增多,差异均有统计学意义(P<0.05)。结论:复智胶囊通过增加海马NMDA阳性细胞表达,提高海马神经元齿状回PS增幅,改善大鼠学习记忆能力,对血管性痴呆模型大鼠海马神经元突触传递长时程增强有明显的改善作用。     

补肾益智方对卵巢切除大鼠海马长时程增强的影响

目的：观察补肾益智方对卵巢切除大鼠海马长时程增强(LTP)的影响。方法：3月龄SD雌性大鼠，随机分为假手术组、模型组、补肾益智方低剂量组、补肾益智方高剂量组、雌激素对照组，模型组行双侧卵巢切除术，补肾益智方高、低剂量组、雌激素对照组分别在卵巢切除术后予补肾益智方灌胃和结合雌激素皮下注射。运用电生理学检测方法，观察大鼠长期雌激素剥夺对大鼠海马长时程增强的影响以及中药补肾益智方的干预作用。结果与结论：卵巢切除大鼠海马齿状回产生LTP的幅度明显低于卵巢保留组，并且维持的时间也较短；雌激素替代和补肾益智方高剂量组的LTP增幅和维持时间与卵巢保留组相比均无明显降低。说明二者使卵巢切除大鼠的突触易化机制得以保护和维持。